Hydraulic steering apparatus for ship&#39;s rudders



Oct. 8, 1957 KNUT HAR TENFJORD 2,808,809

HYDRAULIC STEERING APPARATUS FOR SHIP"S RUDDERS Filed Dec. 8. 1953 fizperz lar United States Patent HYDRAULIC STEERING APPARATUS FOR SHIPS RUDDERS Knut Hfir Tenfjord, Tennfjord, near Alesund, Norway Application December 8, 1953, Serial No. 396,899

Claims priority, application Norway December 10, 1952 2 Claims. (Cl. 121-38) This invention relates to a hydraulic steering apparatus for ships rudders of the kind, in which the rudder head is connected with a piston turnable about its axis and arranged within an annular cylinder, whose curved walls are cylindric surfaces concentric to the rudder head.

The invention is characterized substantially by a semicircular piston operating in nearly one half of the annular cylindric compartment and meshing with the tiller or an arm connected therewith. Suitably the interior, curved wall of the piston cylinder has an aperture through which the tiller or the said arm projects out to the middle portion of the piston and comprises the angle through which the arm has to be turnable. The said aperture forms abutments for the tiller or arm, and the tiller projects loosely out into a recess arranged in the middle portion of the piston. Preferably the cylinder compartment is interrupted on a periferical short portion (partition) which separates two halves of the cylinder compartment and contains valves limiting the pressure in these two halves.

The partition contains two spring-loaded and oppositely operating valves, each of which operates to transmit pressure from one cylinder half to the other one, when the pressure in one of them increases beyond the predetermined limit.

An embodiment of the invention is illustrated in the drawing.

Figure l is an end view of the apparatus.

Figure 2 shows a cross-section on the broken line IIII in Figure 1.

Figure 3 shows the semicircular piston separately turned 90 in relation to the position shown in Figure 1.

On the rudder head 1 is keyed an arm 2, the so-called tiller. Its exterior end 3 projects into a recess 4 in the semi-circular piston 5 which is arranged in the circular compartment of the cylinder 6. This cylinder is composed of two portions, one bottom portion 7 with the hub 8 for the rudder head 1 and a top portion or cover 27. These portions are screwed together by means of bolts in the holes 10 of the four lugs 9, and the joining line between both these portions is shown at 11 in Figure 2.

The cover 27 is provided with an aperture 12, wherein the tiller lies freely. This aperture comprises somewhat more than an angle of 45, viz.: about 45 with addition of the periferic width of the exterior end 3 of the tiller. Aperature 12 has abutments 13 for the tiller 2 as shown in Figure 1, so that these two abutments limit the rotary motion of the tiller in both directions. The semicircular piston 5 is inserted into the cylinder which has rectangular cross-section corresponding to the cross-section of the piston and the end portions 14 of the piston have packings and are arranged tightly in the cylinder compartment.

Figure 1 shows the middle position of the tiller.

Diametrically opposite this position the cylinder is interrupted by a partition 15 containing valves. On one 2,808,809 Patented Oct. 8, 1957 side of this partition a socket 16 is arranged and on the opposite side a socket 17. Through these sockets liquid under pressure, for instance oil, is introduced, for instance in such a manner that in case oil is introduced at 16, it will press the semicylindric piston 5 in clockwise direction together with the tiller 2-3 for adjustment of the rudder. During this adjustment the oil from the opposite piston compartment will pass out through 17. The opposite movement takes place when the tiller is to be turned in the opposite direction.

In the partition 15 two ball valves are arranged. The ball 18 of one valve is by a spring 19 pressed against its seat which through an angular channel 20 is connected with the left hand side of the partition. The other valve ball 21 is pressed by a spring 22 against its seat which by channels 23 is connected with the right hand side of the cylinder. Moreover, the compartment within which the ball 18 moves, is connected through a channel 24 within the right side of the cylinder; correspondingly applies for the valve at 21.

The force with which the balls 18 and 21 press against their seats, may be adjusted by means of screws 25 and 26.

The said valves serve to limit the pressure of the liquid in the piston cylinder, so that an interruption is avoided in case the rudder might be exposed to a too high load or resistance to the adjustment.

If the oil is supplied through 16 to the left hand piston compartment, it will also act upon the valve ball 18 which remains immovable as long as the liquid pressure does not increase beyond the safety limit. When this takes place, however, the liquid will press the ball 18 away from its seat, and is pressed through the channel 24 over to the opposite side of the piston cylinder. The opposite operation takes place as regards the valve ball 21.

I claim:

1. A hydraulic steering apparatus for ships rudder, comprising a curved piston cylinder, the interior space of which is a 360 cylindric compartment divided by a radial and peripherically short partition, a curved semicircular piston operating in approximately one-half of said compartment, a rudder head arranged centrically to the cylinder compartment, a tiller fixedly connected with said rudder head and meshing with its free end loosely with the mid-portion of the piston, and valves arranged in said partition to limit the pressure within the two halves of the compartment enclosed between the portion and the appertaining end face of the piston.

2. A hydraulic steering apparatus for ships rudder, comprising a curved piston cylinder, the interior space of which is a 360 cylindric compartment divided by a radial and peripherically short partition, a curved semicircular piston operating in approximately one-half of said compartment, said piston having in its midportion a recess, a rudder head arranged centrically to the cylinder compartment, a tiller fixedly connected with said rudder head and meshing with its free end loosely in said recess, and valves arranged in said partitions adapted to limit the pressure within the two halves of the compartment enclosed between the portion and the appertaining end face of the piston.

References Cited in the file of this patent UNITED STATES PATENTS Great Britain 1872 

